Safety device



Patented Jan. 22, 1924.

UNITED stares :QP N'r :oral-ee. g

lWILLIAM JIMARTIN, OF' TOLEDQ'OHIO,` ASSIGNOR TO'THE WILLYS-OVERLAND' COM- "PANY,'0F TOLEDO,OHIO, A 'CORPORATION' 0F' OHIO.

. SAFETY i impplicationfled iMayr,

To all ywhom t may cow/cem:

lBe it known that'I,'WrLLnrM :JMARTIM a citizen of Canada, and 1.a subject of the Kin-g of Great Britainand Irelandfresiding A at Toledo, in the county of'Lucas andState of Ohiophave inventedcertain new anduseful Improvements in rSafetyDevices, of which I declare the following to be a full, clear, and exact description.

This inventionrelates ,to improvements in safety devices for use in= connection lwith punch presses, trip hammers, and-similar machines.`

The principal objectief this linvention l'is to v:provide V:improved ysafety .devices which may be used in vconnection with punch presses `or devicesI having.` similar. operating mechanism, they construction of thea safety devices bei-ng such as to Apositively stop movement of the operating parts and itoiprevent a reverse movementwoffthef operating parts suchas is likely toqioccur, and; taking the opera-tor unawares, xmitch ,hisflngers between the dies.

Further objects, andobjects relating to economies of manufacture and details of construction, will definitely appear from the detailed description to follow.

I accomplish the objects of my invention by the devices and means described in the following specifications. My invention isl clearly defined and pointed out in the appended claim.

A structure constituting a preferred embodiment of my invention is illustrated in the accompanying drawing, forming a part of this specification, in which:

Fig. I is a view in front elevation of a punch press equipped with a safety device constructed in accordance with my invention.

Fig. II is a fragmentary, top plan View of the clutch mechanism of the punch press.

Fig. III is a detail` sectional view taken substantially on the line III-III of Figs.

II and IV, and 1 Fig. IV is a fragmentary, detail, sectional view, taken substantially on theA line IV-IV of Fig, III.

In the drawings, similar reference numerals refer to similar parts throughout the several views, and the sectional views are taken looking in the direction of the little arrows at the ends of the section lines.

Considering the numbered parts of the DEVICE.

11918. 'Serial No. Y 232,236.

drawing, kI :have :sho-wn a punch press `comprising the "frame 10 and: the main shaft12 on which the fly wheel orldri'vingpulleyll is;looselyzmounted. The clutch13 is 'slidafbly'.bntfnonerotatably mounted on the main shaft12 .and provided 'with teeth or jaws 111 wliichiareiada-pted to interlock with the aws 15 .mounted on the hub of the fly-wheel 11. Springs 16 are vhoused lwithin the clutch member 13 :and .adapted to press said 'clutcn member laterally on the main shaft 12 so as to bring the jaws 14 and 15 into interlocking engagement, so thatthefmain shaft vi12 :is driven from the fly-wheel .11. The plate-'17 is mounted yonthe hub of the clutchmember 13, sai'dplatehaving an inclined port-ion 18 terminating in` a notch or recess`19. A plunger 20 is mounted in a suitable bearing in theframe 10 and carries a weight at its upper end whichnormallyv tends to bring the end. of theplunger '20 into contact with the huby of they clutch lmember 13, so that the end of the/.plunger4 engagesthe inclined portion 18 and the recess 19 of the bracketv17. iIn the normal operation of the rclutch member 13 and the main shaft 12, turning of the clutch member 13 brings the part 18 into contact with the plunger 20 and the inclination of the part 18 moves the clutch member 13 laterally to one side to bring the jaws 14 and 15 out of interlocking engagement.

The clutch member 13 and therefore the main shaft 12 is held against forward movement by the engagement of the plunger 20 in the notch 19. No means is provided in the usual construction which would prevent a reverse or backward rotation of the shaft 12, and it sometimes happens that the shaft 12 has not moved completely past the top dead -center when the rotation of the shaft is stopped, and hence, the weight of the dies and other parts tends to rotate the shaft 12 backward, allowing the die to come down and crush the ngers of the operator. The plunger 2O is operated by means of the rod 21 connected to the rock shaft 22 and on which is mounted the operating lever 23. In order to prevent inadvertent backward or reverse rotation of the main shaft 12, such as is extremely likely to result in catching and crushing the fingers of the operator, I pro-vide a. ratchet disc 27 which is fastened to the end of the clutch member 13 by means of the bolts 28. A bracket 241 is mounted on the frame l0 and carries a pin 25 on which the pawl 26 is pivoted, this pawl 26 having its end in engagement with t-eeth 29 formed in the periphery of the disc 27. rl`he direction of the pawl 26 and of the teeth 29 is such that they do not interfere with the forward rotation of the main shaft 12 and the clutch member 13, but will engage and interlock to prevent any reverse rotation of these parts. The pawl 26 is sufiieiently wide to remain in engagement with the ratchet when the latter is shifted with the clutch 13.

From the description of the parts given above, the operation of this device can bel 'very readily understood. It is obvious that the member 17 through its co-action with the plunger 2O positively disconnects the clutch and positively arrests forward movement of the shaft l2. It will also be observed that,

by means of the pawl and ratchet disc, the pawl being connected to the frame while the ratchet disc is connected to the clutch member rotating with the main shaft, I have provided means whereby a reverse rotation of the main shaft is prevented, while these means do not in any respect interfere with the forward rotation of the shaft in the usual manner. By these simple and effective means, I have eliminated one of the most dangerous sources of injury to workmen employed on punch presses, or similar machines, as the main shaft, having once been stopped, it is absolutely impossible for it te rotate backward or turn once more unt-i] released by the depression of the lever 23 which is under the control of the workman.

I am aware that the particular embodiment of my invention\vhich I have here shown and described, is susceptible of considerable variation without departing from the spirit thereof, and therefore, I desire to claim my invention broadly, as well as specifically, as indicated by the appended claim.

Having thus described my invention, what I claim as ,new and desire to secure by Letters Patent, is:

In a machine of the class described, ahorizontal shaft, a drive wheel loosely mounted upon the shaft, said drive wheel being provided with a clutch face, a clutch splined to said shaft for movement into and out of engagement with the said drive wheel clutch face, a cam on said clutch, a plunger movable into engagement with said cam to shift the clutch out of engagement with the drive wheel, automatic means for preventing further forward rotation of the clutch after its disengagement with the drive wheel and means lfor preventing the reverse rotation of the clutch at all times, comprising a ratchet wheel rigidly mounted upon the clutch and a pavvl mounted upon a rigid portion of the machine, the lateral proportions of the pawl and ratchet being such as to cause those parts to eo-operate during all positions of the clutch.

In testimony whereof, I aifix my signature.

IVILLIAM J. MARTIN. 

